Canvas-stretcher for harvesting-machines



(No Model.) V

J. F. STBWARD. CANVAS STRBTGHER FOR HARVESTING MACHINES.

No. 406,792. Patented July 9, 1889.

UNITED STATES PATENT OFFICE.

JOHN F. STEVARD, OF CHICAGO, ILLINOIS.

CANVAS-STRETCHER FOR HARVESTlNG-MACHINES.

SPECIFICATION forming part of Letters Patent No. 406,792, dated July 9, 1889.

Application filed November 24. 1886. Serial No. 219,833. (No model.)

To all whoml it may concern/.-

Be it known that I, J oHN F. STEWARD, a citizen of theV United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Mechanism for Stretching Canvas Carrier-Aprons, dac., of which the following is a full, clear, and exact specification,

reference being had to the accompanyingv the sill B by a vertical pivot b2, and extends drawings, forming a part hereof.

My invention has reference to machines in which an endless carrier or conveyer apron is sustained at its ends upon parallelA rollers.

The object of the invention is to provide a simple mechanism for increasing the distance between the rollers to obtain proper tension of the apron and at the same time maintain exact parallelism between the rollers.

For the purposes of illustration I have represented my improvement applied to the platform of a harvesting-machine. With theexception of the parts hereinafter specified, the improvement may be in all respects of ordinary construction, and I have therefore coniined the drawings to 4those portions with which my improvements are immediately associated.

In the accompanying drawings, Figure l is a top plan view of a portion of a harvesterplatform to show the roll for supporting one end of the apron and the mechanism for supporting and adjusting said roll. Fig. 2 is a vertical transverse section on the line .r of Fig. l. Fig. 3 is a longitudinal vertical section on the line y y of Fig. l. Figs. 4 and 5 are respectively an edge view and a plan view of a detail hereinafter described.

Referring to the drawings, A represents the finger-bar, B the rear platform-sill, and C the bottom board, of a harvestingnnachine, constructed and united as usual.

D and E are bars fixed to the sills, as usual, to sustain the edges of the apron.

In carrying my improvement into effect I mount the respective journals of the usual roller c, by which the outer end of the conveyerapron is carried, in horizontal sliding bars a and b, which also assist, like the customary sills, to sustain the edges of the apron. For the purpose of moving these slides simultaneously and equally in an outward direction, I provide the two crossed levers a5 and b', united by the central pivot b4. The lever a5 is pivoted to the finger-bar bythe guard-bolt a, extending thence through aslot in the slide a. and across the platform, and is mounted at the rear end in a mortise in the slide b, to which it may be further connected by a slot and pin b5, if desirable.

The lever h is connected at its rear end to thence forward through a slot in the slide b across the platform into a mortise in the front slide a', which may be further con# nected by the pin b and the slot, if desired.

It will be observed that the two levers applied as above compel the two slides a and b to move equally in unison, thus allowing the roll c to move inward and outward to maintain it at all times parallel with the companion roll, which will be mounted at the opposite end of the platform, as usual.

The parts constructed as above may be adjusted by hand and iixed in position in any suitable manner, or a spring may be, and preferably is, applied to urge the slides out ward and automatically maintain the tension of the apron. I prefer to apply the spring as represented in Figs. 1 and 2, in which d and e represent arms secured rigidly to the respective levers, and extending stubbleward therefrom. Abolt f is passed loosely through the ends of these arms and encircled by a helical spring f, which bears at one end against the arm cl and at the opposite end against an adjustable nut f2 on the bolt. A second nutf, applied to the bolt, bears against the arm e. Under this arrangement, the spring acting to separate the free ends of the arms causes them to urge the lever in a proper direction to force the slides and the roller outward. By turning the nut f2 the spring may be compressed, and thus the tension applied to the apron increased.

The slides a and h may be supported and guided in any appropriate manner; but I recommend the construction shown in the drawings. The slide a is sustained at its outer end by a plate a3, secured to the fingerbar by one of the guard-bolts and extended thence rearward through a horizontal slot in the slide, and provided with a pin a4 to hold IOO the slide forward to its place. At the stubble end this slide receives support from the lever a5, which is extended through a horizontal slot therein and provided with a pin CL2 to hold the slide forward.

The slide b is supported in a similar manner at its inner end by the lever b passing through a horizontal slot therein, and is supported at its outer end by a bolt b3 passing through a horizontal slot into the rear sill.

The lever-arms d and e may be formed and secured to the levers in any suitable manner; but I recommend their construction of L form, as shownin Figs. 4 and 5, with ianges d2 to embrace the levers and receive fastening bolts or rivets.

Instead of applying the spring between the arms, as shown, it may be connected to the pivot which unites the levers Vand extended thence grainward to a fixed support, as shown in dotted lines in Fig. l.

The ends of the levers must be slotted at their sustaining-pivots or the connectingpivot passed through a slot to prevent the parts from cramping as the levers change position.

Having thus described my invention, what I claim is- 1. In combination with the platform-frame, the apron-sustaining roll, the two slides supporting said roll, and the crossed levers united by the pivot and connected each at one end to the frame and at the other end to one of the slides, whereby the two slides are compelled to move simultaneously and equally.

2. In a harvester, the combination of a suitable supporting-frame, an apron-carryin g roll, two slides sustaining the ends of said roll, two

crossed levers pivoted together and connecting at their opposite ends the respective slides with the frame, and a' spring, substantially as described, acting to carry the roller outward and thereby stretch the apron.

3. In combination with the supportingframe, the apron-carrying roll, and the rollsupporting slides, the crossed levers connecting at their opposite ends the respective slides with the frame and pivoted together, the rigid arms on said levers, and a spring acting between said arms.

4. The roll, the roll-carrying slides a b, the crossed levers connect-ed to the frame and to the respective slides at opposite ends and pivoted together, the arms d e, secured rigidly to the respective levers, the bolt f the spring f 5 5 thereon, and the adjustable nut f2, said elements combined substantially as described and shown.

5. In combination with the supportingframe and the two roll-supporting slides provided with slots, the crossed levers extending through the slots in the slides and connected at their opposite ends to the frame and the slides, substantially as described,whereby the levers are adapted to serve the twofold purpose of adjusting and supporting the slides.

v 6. In combination with the roll-supporting slide, the finger bar and the guard-iingcr bolted thereto, as usual, and the slide-sus taining plate a3, secured to the bar by the vertical linger-bolt.

JOHN F. STEWARD. Vitnesses:

F. C. PIERs, WILFRED TWINCH. 

